Formula: Cu3Se2
Origin of name: after locality Sierra de Umango, La Rioja province, Argentina
Crystal system: Tetragonal
Crystal class: -42m
Twinning: may have lamellar twinning
Unit cell: a = 6.4024, c = 4.2786
Colour: Blue black, brownish black, red violet, tarnishes to a dull iridescent purple
Diaphaneity: Opaque
Luster: Metallic
Habit: Massive, granular, as disseminated small grains, individual grains commonly exhibit rectangular outlines
Hardness: 3
Specific gravity: 6.44-6.49
Cleavage: 2; poor, rectangular
Tenacity: Brittle, uneven, subconchoidal fracture
Streak: Black
Synonyms/varieties:
Comments:
| Back to Alphabetical list | Colour photos | Optical properties/Thin sections | SEM images | TEM images | vibrational spectra description | IR spectra | Raman spectra | N-IR spectra | F-IR spectra | IES spectra |